A biochemical automatic analyzing device is known which performs biochemical analysis on a sample, such as blood, urine, or stool, by injecting the sample and a reagent into a transparent measurement container called a sample cell to react them with each other, and then optically measuring the coloration due to the reaction of the reaction solution including the sample and the reagent (refer to Patent Document 1, for example).
In this regard, after both the reagent and the sample are injected into the sample cell, the reagent and the sample are stirred in the sample cell in order to react with each other favorably and uniformly. For a biochemical automatic analyzing device, a stirring mechanism which mixes a reaction solution in a short period of time is demanded in terms of improvement in throughput. Further, in terms of reduction in the consumption volume of reagent, there is a demand for a stirring mechanism that mixes a reaction solution in a minute sample cell with which a small volume of reaction solution can be analyzed.
Patent Document 2 proposes a method of causing a stirring rod to perform a rotational movement and a reciprocal rectilinear movement in a horizontal direction at the same time for efficient stirring in a short period of time. However, analysis has to be performed with a narrow sample cell in order to handle a smaller volume of reaction solution. This requires the stirring to be performed with a limited horizontal movement.